Re: [libvirt] [PATCH 4/4] qemu: Use correct flags for ABI stability check in SaveImageUpdateDef

https://bugzilla.redhat.com/show_bug.cgi?id=1183869 Soo. you've successfully started yourself a domain. And since you want

to use it on your host exclusively you are confident enough to passthrough the host CPU model, like this: <cpu mode='host-passthrough'/> Then, after a while, you want to save the domain into a file (e.g. virsh save dom dom.save). And here comes the trouble. The file consist of two parts: Libvirt header (containing domain XML among other things), and qemu migration data. Now, the domain XML in the header is formatted using special flags (VIR_DOMAIN_XML_SECURE | VIR_DOMAIN_XML_UPDATE_CPU | VIR_DOMAIN_XML_INACTIVE | VIR_DOMAIN_XML_MIGRATABLE). Then, on your way back from the bar, you think of changing something in the XML in the saved file (we have a command for it after all), say listen address for graphics console. So you successfully type in the command: virsh save-image-edit dom.save Change all the bits, and exit the editor. But instead of success you're left with sad error message: error: unsupported configuration: Target CPU model <null> does not match source Pentium Pro Sigh. Digging into the code you see lines, where we check for ABI stability. The new XML you've produced is compared with the old one from the saved file to see if qemu ABI will break or not. Wait, what? We are using different flags to parse the XML you've provided so we were just lucky it worked in some cases? Yep, that's right.

Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; --- src/qemu/qemu_driver.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index 8f0cf2b..19dfce4 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -5734,8 +5734,8 @@ qemuDomainSaveImageUpdateDef(virQEMUDriverPtr driver, if (!(newdef_migr = qemuDomainDefCopy(driver, newdef, - VIR_DOMAIN_XML_MIGRATABLE | - VIR_DOMAIN_XML_SECURE))) + QEMU_DOMAIN_FORMAT_LIVE_FLAGS || + VIR_DOMAIN_XML_MIGRATABLE)))

goto cleanup; if (!virDomainDefCheckABIStability(def, newdef_migr)) { -- 2.0.5 -- libvir-list mailing list libvir-list(a)redhat.com https://www.redhat.com/mailman/listinfo/libvir-list